The present invention relates to a sound signal reproducing apparatus for supplying sound signals for a plurality of channels to speakers via sound amplifier circuits, which apparatus is used in for example a home AV theater system, a multi-channel surround sound system and the like.
Recently, a sound signal reproducing apparatus has been proposed which forms a home AV theater as shown in FIG. 5, for example, and provides a sense of presence in a movie theater, a concert hall or the like by supplying sound signals for a plurality of channels, for example six channels to speakers via sound amplifier circuits.
In FIG. 5, reference numeral 1 denotes a listener; 2FL denotes a front left speaker; 2C denotes a center speaker; 2FR denotes a front right speaker; 2RL denotes a rear left speaker; 2RR denotes a rear right speaker; and 2W denotes a subwoofer.
When the sound signal reproducing apparatus supplying the sound signals for the plurality of channels, for example the six channels to the speakers via the sound amplifier circuits is to ensure that a maximum output of each of the channels is of the same magnitude as in a conventional apparatus, the sound signal reproducing apparatus requires a power supply circuit providing an extremely high power and also requires a cooling device of an extremely large size for cooling a power transistor used in the power supply circuit.
However, the sound signal reproducing apparatus in normal use in an ordinary household does not continuously produce the maximum output in all of the plurality of channels, for example the six channels.
Sound pressure required by the listener 1 is generally constant irrespective of the number of channels. When the listener 1 listens to sound signals of the plurality of channels, for example the six channels, output per channel can be lowered by adjusting the sound volume.